A thermal transfer film may be used as a donor film in formation of patterns. The thermal transfer film includes a base film and a light-to-heat conversion layer formed on the base film, in which a transfer layer including an organic luminescent material is formed on the light-to-heat conversion layer in formation of patterns. The light-to-heat conversion layer is required to prevent decrease in optical density for light-induced thermal transfer and to have low and uniform surface roughness for uniform thermal transfer. The thermal transfer film may further include an interlayer on the light-to-heat conversion layer. Surface roughness of the interlayer can become an important factor capable of reducing transfer failure of the transfer layer.
The base film is a film subjected to coating and may include a primer (generally, particles) formed using materials such as polyurethane, polyester, and the like on a surface thereof. The primer provides good slip properties to the base film and prevents generation of scratches upon roll winding.
The thermal transfer film may be provided as a final product through roll winding after manufacture thereof. FIG. 3 shows a stack (a) of a thermal transfer film wound on a roll 2 in a process of manufacturing a thermal transfer film 1, and a thermal transfer film (b) produced from the stack (a). Referring to FIG. 3, the stack (a) of the thermal transfer film is produced by winding a thermal transfer film 1, which includes a base film 10 having a primer 13 formed thereon, a light-to-heat conversion layer 11 and an interlayer 12, on a roll 2. In this case, indentations 14 having a shape corresponding to the shape of the primer can be formed on the interlayer 12 of the thermal transfer film by winding pressure of the roll and the primer 13 of the baser film 10 of the thermal transfer film. The indentations 14 can deteriorate surface roughness of the interlayer and can cause transfer failure of the transfer layer upon light-to-heat transfer, since the transfer layer is formed on the interlayer. Although the thermal transfer film is shown as being composed of the base film, the light-to-heat conversion layer, and the interlayer in FIG. 3, the indentations can be formed on a thermal transfer film composed of a base film and a light-to-heat conversion layer.